tshoot lab manual...

i thought i'd avoid much commentary about the tshoot net acad lab manual, but this is worth a mention...

look at this:

DLS1#sh run int f0/5
Building configuration...

Current configuration : 163 bytes
!
interface FastEthernet0/5
 description FE to R1
 no switchport
 ip address 10.1.2.1 255.255.255.252
 speed 100
 duplex full
 spanning-tree bpduguard enable
end

note this is a distribution switch... note it is connected to a router... it is a routed port and it has bpduguard on it...  i remember a long time ago watching an anthony sequiera (sic) video where he demonstrates how to errdisable a switchport using a router... about a week ago i was watching jeremy cioara vids on tshoot, where he had to troubleshoot a situation just like this...

like chucky says to the interviewers in Good Will Hunting, "you're suspect..."

DLS1#sh int f0/5 sw
Name: Fa0/5
Switchport: Disabled

DLS1#sh spann int f0/5
no spanning tree info available for FastEthernet0/5

DLS1#sh int f0/5
FastEthernet0/5 is up, line protocol is up (connected)
  Hardware is Fast Ethernet, address is 0016.c706.96c2 (bia 0016.c706.96c2)
  Description: FE to R1
  Internet address is 10.1.2.1/30
  MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec,
     reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation ARPA, loopback not set
  Keepalive set (10 sec)
  Full-duplex, 100Mb/s, media type is 10/100BaseTX
  input flow-control is off, output flow-control is unsupported
  ARP type: ARPA, ARP Timeout 04:00:00
  Last input 00:00:02, output 00:00:03, output hang never
  Last clearing of "show interface" counters never
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
  Queueing strategy: fifo
  Output queue: 0/40 (size/max)
  5 minute input rate 0 bits/sec, 0 packets/sec
  5 minute output rate 0 bits/sec, 0 packets/sec
     26086 packets input, 2944859 bytes, 0 no buffer
     Received 10943 broadcasts (0 IP multicasts)
     0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
     0 watchdog, 10899 multicast, 0 pause input
     0 input packets with dribble condition detected
     23227 packets output, 2507991 bytes, 0 underruns
     0 output errors, 0 collisions, 1 interface resets
     0 babbles, 0 late collision, 0 deferred
     0 lost carrier, 0 no carrier, 0 PAUSE output
     0 output buffer failures, 0 output buffers swapped out

i hate to say it but sh run int f0/5 is your only detection...

this is how you do it...

R1(config)#bridge 1 protocol ieee
R1(config)#int f0/0
R1(config-if)#bridge-group 1

DLS1#sh int f0/5
FastEthernet0/5 is up, line protocol is up (connected)
  Hardware is Fast Ethernet, address is 0016.c706.96c2 (bia 0016.c706.96c2)
  Description: FE to R1

DLS1(config)#int f0/5
DLS1(config-if)#sw
DLS1(config-if)#
.Jan 22 16:48:07.180: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/5, changed state to down
DLS1(config-if)#do
.Jan 22 16:48:09.202: %LINK-3-UPDOWN: Interface FastEthernet0/5, changed state to up
.Jan 22 16:48:10.208: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/5, changed state to up
DLS1(config-if)#do
.Jan 22 16:48:10.619: %SPANTREE-2-BLOCK_BPDUGUARD: Received BPDU on port Fa0/5 with BPDU Guard enabled. Disabling port.
DLS1(config-if)#do
.Jan 22 16:48:10.619: %PM-4-ERR_DISABLE: bpduguard error detected on Fa0/5, putting Fa0/5 in err-disable state
DLS1(config-if)#do
.Jan 22 16:48:11.634: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/5, changed state to down
DLS1(config-if)#do
.Jan 22 16:48:12.632: %LINK-3-UPDOWN: Interface FastEthernet0/5, changed state to down

DLS1#sh int f0/5
FastEthernet0/5 is down, line protocol is down (err-disabled)
  Hardware is Fast Ethernet, address is 0016.c706.9687 (bia 0016.c706.9687)
  Description: FE to R1

that ain't nice...